How Legal Is Marijuana?

Image from the National Cancer Institute. A map shows the U.S. states and territories that had approved the medical use of cannabis prior to the 2016 elections.

The NIDA Blog Team

October 11, 2016

Update: On Nov. 8, 2016, voters in eight states made changes to their marijuana laws, according to uncertified results. California, Maine, Massachusetts, and Nevada legalized marijuana for adult recreational use. Arkansas, Florida, Montana, and North Dakota legalized marijuana for medical use. The details of the laws and when they go into effect vary by state.

Original post, current as of Oct. 11, 2016:

There’s been a lot of talk in the U.S. lately about legalizing marijuana. Maybe you’ve heard stories in the news about some states that have legalized weed (or are debating whether to do that) and wondered, what does that mean for you?

Recreational marijuana

First, let’s get the obvious out of the way: If you’re a teen, it’s never legal to use marijuana recreationally (that is, just to get high).

Marijuana is also still illegal under U.S. federal law, even in states that have passed laws to make it legal under state law.

Confused yet? Okay, so what about those state laws?

The District of Columbia and four states (Alaska, Colorado, Oregon, and Washington) allow adults to use marijuana recreationally. While the laws in these places vary, all of them prohibit people under the age of 21 from using marijuana recreationally.

So far, 25 states and D.C. have passed laws to let people use marijuana with recommendations from their doctors (and sometimes by fulfilling other requirements, like having a medical marijuana license). The federal government has decided not to challenge those laws to any great extent. But people who buy marijuana in a state where it’s legal (for medicinal or recreational use) cannot take it across state lines into a state where it is not legal. So it remains a confusing issue.

Marijuana hasn’t been approved by the Food and Drug Administration (FDA), and that approval is necessary to grow and sell medicine in this country. But researchers are studying possible medical uses for marijuana and some of the chemicals it contains. The Drug Enforcement Administration (DEA), which enforces marijuana laws in the U.S., recently said it would increase the number of places allowed to grow the plant for research purposes in hopes of making it easier for more scientists to study marijuana.

So just to repeat, nothing in the law has changed for teens; using weed to get high is still illegal, wherever you live in the U.S. Depending on what scientists learn about marijuana’s value as medicine, it may (or may not) become legal for more people with certain health problems.

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We're sorry to hear about your struggles and appreciate you reaching out to us. As a federal scientific research agency, we are unable to provide medical advice, so please contact a doctor if you have concerns. If you feel you are in crisis, please have someone drive you to the emergency room or call 911. You can get information about drug abuse treatment programs at https://findtreatment.samhsa.gov/. If you aren't sure what to do or just want to talk to someone, you can contact the National Suicide Prevention Lifeline at http://www.suicidepreventionlifeline.org/.

We know little about the medical effects of marijuana and more research is needed. Marijuana has been used to treat lots of health conditions, but for most of these health conditions there is almost no data regarding whether it really works. But research is telling us a lot about the negative consequences of marijuana use and its impact on the brain, body, and behavior. Marijuana use among adolescents, among other things, is linked with poor concentration, memory, and ability to learn new information. So, from a health perspective, there is no evidence to support adolescent use of marijuana for health conditions but lots of evidence of its negative impact. Despite those negative effects, there is no evidence that marijuana kills neurons.

Actually, yes, marijuana can be addictive. Someone who regularly uses marijuana may continue to use it despite negative consequences in their life. Approximately 10 percent of users may develop what is called a marijuana use disorder—problems with their health, school, friendships, family or other conflicts in their life. A serious substance use disorder is commonly called an addiction. This means a person can’t stop using marijuana even though using it gets in the way of daily life. People who begin using marijuana before the age of 18 are 4 to 7 times more likely than adults to develop a marijuana use disorder.

The National Institute on Drug Abuse Blog Team. How Legal Is Marijuana?. National Institute on Drug Abuse for Teens website. https://teens.drugabuse.gov/blog/post/how-legal-marijuana. October 11, 2016. Accessed

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